History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
Accordingly the accursed persons were driven out not only by the Athenians but also at a later time by Cleomenes the Lacedaemonian, with the help of a faction of the Athenians, during a civil strife, when they drove out the living and disinterred and cast out the bones of the dead. Afterwards, however, they were restored, and their descendants are still in the city.
It was this "curse " that the Lacedaemonians now bade the Athenians drive out, principally, as they pretended, to avenge the honour of the gods, but in fact because they knew that Pericles son of Xanthippus was implicated in the curse on his mother's side,[*](Pericles was a descendant in the sixth generation from Megacles, his mother Agariste being niece of the Alcmaeonid Cleisthenes (Hdt 6.131.).) and thinking that, if he were banished, they would find it easier to get from the Athenians the concessions they hoped for.
They did not, however, so much expect that he would suffer banishment, as that they would discredit him with his fellow-citizens, who would feel that to some extent his misfortune[*](As belonging to the accursed family.) would be the cause of the war.
For being the most powerful man of his time and the leader of the state, he was opposed to the Lacedaemonians in all things, and would not let the Athenians make concessions, but kept urging them on to the war.